FARR: QUADRIPARTITION IN SISYRINCHIUM 53 
Guérin (10) has made a study of the development of the 
anthers and pollen of the labiates, but passes over the matter 
of division of the mother-cell into the four microspores as ex- 
hibiting nothing of particular interest. Valleau (26) in connec- 
tion with his study of sterility in the strawberry has published 
a careful account of pollen-formation. He describes in detail 
the formation of the material about the protoplast which in 
other forms has been considered as the thickening of the cell- 
wall. However, in Fragaria, it seems to be a secretion from the 
protoplast rather than the thickening of the wall. With regard 
to the formation of the partitions the author does not commit 
himself. He states: 
he daughter nuclei are soon formed, and walls are laid down between 
them, dividing the cytoplasm evenly. The cells gradually split apart, 
separating the four microspores and allowing the entrance between them 
of the viscous material. 
It might be concluded from this description that cell-plates 
accomplish the partitioning and that the invagination of the 
peripheral material is simply incidental to the rounding. up 
process. No figures of these stages are shown. Quite recently 
R. R. Gates (9) has published a preliminary account of reduction 
divisions in the pollen-mother-cells of Lactuca sativa. In this 
paper there is described a quadripartition by furrowing rather 
than by cell-plates, just as the writer (4) had previously reported 
for Helianthus and Ambrosia, as well as in other groups of 
Dicotyledons. No drawings are given by Gates, but a para- 
graph is devoted to a description of the process. He mentions 
that furrows may be formed either in the presence or the absence 
of spindle fibers but does not describe the latter instance any 
farther. It is stated that an ephemeral cell-plate occasionally 
is found after the heterotypic division, but it never functions 
and no cell-plate is present after the homoeotypic mitosis. 
The most careful recent study of this question is that of 
Mrs. Wanda K. Farr (6), in which she gives figures and des- 
criptions of quadripartition in the pollen-mother-cells of Cobaea 
scandens. These support the writer’s contention (4) that 
cell-division by furrowing is common in the pollen-mother-cells 
of Dicotyledons. It is interesting to note that the first descrip- 
tion of cell-division in any plant is probably that by Brongniart 
in 1827 on the pollen-mother-cells of Cobaea scandens (2), in 
which it is indicated that the process is furrowing, though, of 
